USB ports are found in many electronic host devices, such as desktop computers, automobile dashboard consoles and in battery-powered portable devices such as laptop computers, tablets, mobile phones, e-readers and MP3 players. USB compatible systems typically include interface chips mounted to an internal circuit board to interface USB data and power connections to host system circuitry such as power circuits and host processors. USB ports are accessed using standardized USB cable connections to provide serial communications between devices, as well as electrical power transfer for charging and operating battery-powered peripheral devices. Dedicated charging devices are also available having multiple USB ports for charging various portable devices, which may include circuitry for fast charging certain peripheral devices, and many desktop and laptop computers include multiple USB ports for data transfer and/or peripheral device charging.
USB power delivery (USB-PD) and Type-C specifications describe delivery of higher power over USB cables and connectors to provide a universal power plug for devices that may accommodate more than 5 V charging power, and the USB-PD specification defines communications for negotiating voltage and current levels for power transfer from a source port to a sink port, where the power negotiation communications is independent from the normal USB communications. The USB port controller for USB-PD systems typically includes a physical layer as well as overlying protocol and policy engine layers for managing the USB-PD messaging. The physical layer implements Biphase Mark Coding (BMC) for message exchange over a configuration channel (CC) wire or line of the USB cable. Systems having multiple USB ports, however, require a separate USB port controller for each port, with each conventional port controller implementing the physical, protocol and policy engine layers.